diff --git a/src/unittests/java/MakeItFit/activities/types/RepetitionsTest.java b/src/unittests/java/MakeItFit/activities/types/RepetitionsTest.java
index e0947b0..5961707 100644
--- a/src/unittests/java/MakeItFit/activities/types/RepetitionsTest.java
+++ b/src/unittests/java/MakeItFit/activities/types/RepetitionsTest.java
@@ -2,14 +2,14 @@
 
 import java.util.UUID;
 
+import MakeItFit.utils.MakeItFitDate;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotSame;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Test;
-
-import MakeItFit.utils.MakeItFitDate;
 
 public class RepetitionsTest {
     private TestRepetitions activity;
diff --git a/src/unittests/java/MakeItFit/time/TimeManagerTest.java b/src/unittests/java/MakeItFit/time/TimeManagerTest.java
new file mode 100644
index 0000000..26110b2
--- /dev/null
+++ b/src/unittests/java/MakeItFit/time/TimeManagerTest.java
@@ -0,0 +1,64 @@
+package MakeItFit.time;
+
+import MakeItFit.utils.MakeItFitDate;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class TimeManagerTest {
+
+    private MakeItFitDate date;
+
+    @BeforeEach
+    void setup() {
+        date = MakeItFitDate.of(2024, 5, 10);
+    }
+
+    @Test
+    void testDefaultConstructorInitializesWithCurrentDate() {
+        TimeManager manager = new TimeManager();
+        assertNotNull(manager.getCurrentDate());
+    }
+
+    @Test
+    void testConstructorWithCustomDate() {
+        TimeManager manager = new TimeManager(date);
+        assertEquals(date, manager.getCurrentDate());
+    }
+
+    @Test
+    void testGetCurrentDateReturnsCorrectDate() {
+        TimeManager   manager = new TimeManager(date);
+        MakeItFitDate current = manager.getCurrentDate();
+        assertEquals(date, current);
+    }
+
+    @Test
+    void testAdvanceTimeWithPositiveDays() {
+        TimeManager   manager      = new TimeManager(date);
+        MakeItFitDate advancedDate = manager.advanceTime(5);
+
+        MakeItFitDate expectedDate = date.plusDays(5);
+        assertEquals(expectedDate, advancedDate);
+        assertEquals(expectedDate, manager.getCurrentDate());
+    }
+
+    @Test
+    void testAdvanceTimeWithZeroDays() {
+        TimeManager   manager      = new TimeManager(date);
+        MakeItFitDate advancedDate = manager.advanceTime(0);
+
+        assertEquals(date, advancedDate);
+    }
+
+    @Test
+    void testAdvanceTimeWithNegativeDaysThrowsException() {
+        TimeManager              manager = new TimeManager(date);
+        IllegalArgumentException exception =
+            assertThrows(IllegalArgumentException.class, () -> { manager.advanceTime(-1); });
+        assertEquals("Days must be a positive number.", exception.getMessage());
+    }
+}